In 4-quart Dutch oven, place yams and enough water to cover. Heat to boiling; reduce heat. Cover; simmer 20 to 25 minutes or until tender when pierced with fork. Drain. When yams are cool enough to handle, slip off skins.
Heat oven to 375°F. Spray 8-inch square (2-quart) glass baking dish with cooking spray.
In large bowl, beat eggs, vanilla bean paste and salt until frothy. Add yams; mash until no lumps remain. Add pineapple, granulated sugar, coconut milk and 1/3 cup of the butter; mix well. Spoon into baking dish. In small bowl, mix coconut, brown sugar, pecans, flour and remaining 1/3 cup butter. Sprinkle evenly over casserole.
Bake uncovered 30 to 35 minutes or until top is golden brown. Let stand 10 minutes before serving.